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Don't emit lifetime markers when msan is enabled 

In r235553, Clang started emitting lifetime markers more often. This
caused false negative in MSan, because MSan only poisons all allocas
once at function entry. Eventually, MSan should poison allocas at
lifetime start and probably also lifetime end, but until then, let's not
emit markers that aren't going to be useful.

llvm-svn: 235613
This commit is contained in:
Reid Kleckner 2015-04-23 18:07:13 +00:00
parent 6489d7b949
commit 1ef49218b3
2 changed files with 12 additions and 3 deletions
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5
clang/lib/CodeGen/CGDecl.cpp
View File

@ -856,6 +856,11 @@ llvm::Value *CodeGenFunction::EmitLifetimeStart(uint64_t Size,
if (CGM.getCodeGenOpts().OptimizationLevel == 0)
return nullptr;
// Disable lifetime markers in msan builds.
// FIXME: Remove this when msan works with lifetime markers.
if (getLangOpts().Sanitize.has(SanitizerKind::Memory))
return nullptr;
llvm::Value *SizeV = llvm::ConstantInt::get(Int64Ty, Size);
llvm::Value *Args[] = {
SizeV,

10
clang/test/CodeGen/cleanup-destslot-simple.c
View File

@ -1,4 +1,8 @@
// RUN: %clang_cc1 -O1 -triple x86_64-none-linux-gnu -emit-llvm -gline-tables-only %s -o - | FileCheck %s
// RUN: %clang_cc1 -O1 -triple x86_64-none-linux-gnu -emit-llvm -gline-tables-only %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=LIFETIME
// We shouldn't have markers at -O0 or with msan.
// RUN: %clang_cc1 -O0 -triple x86_64-none-linux-gnu -emit-llvm -gline-tables-only %s -o - | FileCheck %s --check-prefix=CHECK
// RUN: %clang_cc1 -O1 -triple x86_64-none-linux-gnu -emit-llvm -gline-tables-only %s -o - -fsanitize=memory | FileCheck %s --check-prefix=CHECK
// There is no exception to handle here, lifetime.end is not a destructor,
// so there is no need have cleanup dest slot related code
@ -9,7 +13,7 @@ int test() {
return *p;
// CHECK: [[X:%.*]] = alloca i32
// CHECK: [[P:%.*]] = alloca i32*
// CHECK: call void @llvm.lifetime.start(i64 4, i8* %{{.*}})
// CHECK: call void @llvm.lifetime.start(i64 8, i8* %{{.*}})
// LIFETIME: call void @llvm.lifetime.start(i64 4, i8* %{{.*}})
// LIFETIME: call void @llvm.lifetime.start(i64 8, i8* %{{.*}})
// CHECK-NOT: store i32 %{{.*}}, i32* %cleanup.dest.slot
}